Integration of power generation with methane reforming

ABSTRACT

The system includes a methane reformer, a combined cycle power generator, and a switch. The reformer is configured to react methane with steam. The combined cycle power generator includes a steam turbine, a gas turbine, a power generator, and a water boiler. The steam turbine is configured to rotate in response to receiving steam. The gas turbine is configured to rotate in response to receiving a mixture of fuel and air. The power generator is configured to convert rotational energy from the steam turbine and the gas turbine into electricity. In a first position, the switch is configured to direct exhaust from the gas turbine to the reformer, thereby providing heat to the reformer. In a second position, the switch is configured to direct exhaust from the gas turbine to the water boiler, thereby providing heat to the water boiler to generate steam.

TECHNICAL FIELD

This disclosure relates to integrating power generation with methanereforming.

BACKGROUND

Methane reforming involves the use of a catalyst to produce hydrogenfrom methane. Steam methane reforming is a type of methane reformingthat reacts methane with steam in the presence of a catalyst to producecarbon monoxide and hydrogen. The reaction associated with steam methanereforming is endothermic and requires heat to maintain desirablereaction conditions. Fuel is often burned to provide a source of heat.

SUMMARY

This disclosure describes technologies relating to integrating powergeneration with methane reforming in ammonia production to improvethermal efficiency.

Certain aspects of the subject matter described can be implemented as asystem. The system includes a reformer, a combined cycle powergenerator, and a switch. The reformer is configured to react methanewith steam to produce a reformer product stream that includes carbonmonoxide and hydrogen. The combined cycle power generator is fluidicallycoupled to the reformer. The combined cycle power generator includes asteam turbine, a gas turbine, a power generator, and a water boiler. Thesteam turbine is configured to rotate in response to receiving steam.The gas turbine is configured to rotate in response to receiving amixture of fuel and air. The power generator is coupled to the steamturbine and the gas turbine. The power generator is configured toconvert rotational energy from the steam turbine and rotational energyfrom the gas turbine into electricity. The water boiler is fluidicallycoupled to the steam turbine. The water boiler is configured to generatesteam from water in response to receiving heat. The switch can adjustbetween a first position and a second position. In the first position,the switch is configured to direct exhaust from the gas turbine to thereformer, thereby providing heat to the reformer. In the secondposition, the switch is configured to direct exhaust from the gasturbine to the water boiler, thereby providing heat to the water boiler.

This, and other aspects, can include one or more of the followingfeatures. The system can include an ammonia production system. Thereformer can be a part of the ammonia production system. The reformercan include a reformer reactor and a second water boiler. The reformerreactor can be configured to discharge the reformer product stream. Thereformer product stream can include methane. The second water boiler canbe configured to generate steam in response to receiving the reformerproduct stream. The ammonia production system can include a secondaryreformer in fluid communication with the reformer reactor. The secondaryreformer can be configured to receive and react the reformer productstream and a heated stream to produce a second reformer product stream.The heated stream can include oxygen, nitrogen, or any combination ofthese. The second reformer product stream can include carbon monoxide,nitrogen, hydrogen, methane, or any combination of these. The ammoniaproduction system can include a carbon monoxide converter. The carbonmonoxide converter can be in fluid communication with the secondaryreformer. The carbon monoxide converter can be configured to receive andreact the second reformer product stream and steam to produce aconverter product stream. The converter product stream can includecarbon dioxide, hydrogen, nitrogen, water, or any combination of these.The ammonia production system can include a first condenser. The firstcondenser can be in fluid communication with the carbon monoxideconverter. The first condenser can be configured to receive and cool theconverter product stream. The first condenser can be configured todischarge a liquid portion of the converter product stream and a vaporportion of the converter product stream. The liquid portion of theconverter product stream can include water. The vapor portion of theconverter product stream can include carbon dioxide, hydrogen, nitrogen,or any combination of these. The ammonia production system can include afirst compressor. The first compressor can be in fluid communicationwith the first condenser. The first compressor can be configured toreceive and increase a pressure of the vapor portion of the converterproduct stream. The ammonia production system can include a carbondioxide absorber in fluid communication with the first compressor. Thecarbon dioxide absorber can be configured to contact water with thevapor portion of the converter product stream from the first compressorto facilitate transfer of carbon dioxide from the vapor portion of theconverter product stream to the water. The carbon dioxide absorber canbe configured to discharge a water stream and an absorber productstream. The water stream can include carbon dioxide. The absorberproduct stream can include hydrogen and nitrogen. The ammonia productionsystem can include a second compressor. The second compressor can be influid communication with the carbon dioxide absorber. The secondcompressor can be configured to receive and increase a pressure of theabsorber product stream. The ammonia production system can include apre-heater. The pre-heater can be in fluid communication with the secondcompressor. The pre-heater can be configured to receive and increase atemperature of the absorber product stream. The ammonia productionsystem can include an ammonia reactor. The ammonia reactor can be influid communication with the pre-heater. The ammonia reactor can beconfigured to receive the absorber product stream and react the hydrogenand nitrogen of the absorber product stream to produce an ammoniareactor product stream. The ammonia reactor product stream can includeammonia. The ammonia production system can include a second condenser.The second condenser can be in fluid communication with the ammoniareactor. The second condenser can be configured to receive and cool theammonia reactor product stream. The ammonia reactor product stream caninclude hydrogen, nitrogen, or any combination of these. The secondcondenser can be configured to discharge a liquid portion of the ammoniareactor product stream and a vapor portion of the ammonia reactorproduct stream. The liquid portion of the ammonia reactor product streamcan include ammonia. The vapor portion of the ammonia reactor productstream can hydrogen, nitrogen, or any combination of these. The ammoniaproduction system can include an ammonia storage vessel. The ammoniastorage vessel can be in fluid communication with the second condenser.The ammonia storage vessel can be configured to receive and store theliquid portion of the ammonia reactor product stream. The ammoniaproduction system can include a third compressor. The third compressorcan be in fluid communication with the second condenser. The thirdcompressor can be configured to receive and increase a pressure of thevapor portion of the ammonia reactor product stream. The pre-heater canbe in fluid communication with the third compressor. The pre-heater canbe configured to receive and increase a temperature of the vapor portionof the ammonia reactor product stream, such that the vapor portion ofthe ammonia reactor product stream can be recycled to the ammoniareactor. The switch can include a baffle configured to swing between thefirst position and the second position. The switch can include a firstgate and a second gate. In the first position, the first gate can beclosed and configured to obstruct a flow path between the gas turbineand the water boiler to prevent fluid from flowing from the gas turbineto the water boiler. In the first position, the second gate can be openand configured to allow fluid to flow in a flow path between the gasturbine and the reformer. In the second position, the first gate can beopen and configured to allow fluid to flow in the flow path between thegas turbine and the water boiler. In the second position, the secondgate can be closed and configured to obstruct the flow path between thegas turbine and the reformer to prevent fluid from flowing from the gasturbine to the reformer.

Certain aspects of the subject matter described can be implemented as amethod. Methane and steam are flowed to a reformer. The methane andsteam are reacted by the reformer to produce a reformer product stream.The reformer product stream includes carbon monoxide and hydrogen. Steamis flowed to a steam turbine, thereby causing the steam turbine torotate. Electricity is generated by a power generator coupled to thesteam turbine, in response to rotation of the steam turbine. Fuel andair are flowed to a gas turbine, thereby causing the gas turbine torotate. Electricity is generated by the power generator coupled to thegas turbine, in response to rotation of the gas turbine. Exhaust fromthe gas turbine is directed to the reformer by a switch in a firstposition. Directing exhaust from the gas turbine to the reformerprovides heat to the reformer.

This, and other aspects, can include one or more of the followingfeatures. The switch can be adjusted from the first position to a secondposition, thereby directing (by the switch in the second position)exhaust from the gas turbine to a water boiler to provide heat to thewater boiler. Steam can be generated by the water boiler in response toreceiving heat via the exhaust from the gas turbine. The reformerproduct can include methane. The reformer can include a reformer reactorand a second water boiler. The reformer product stream can be flowedfrom the reformer reactor to the second water boiler to provide heat tothe second water boiler. Steam can be generated by the second waterboiler in response to receiving heat via the reformer product streamfrom the reformer reactor. The reformer product stream and a heatedstream can be flowed to a secondary reformer. The heated stream caninclude oxygen, nitrogen, or any combination of these. The reformerproduct stream and the heated stream can be reacted by the secondaryreformer to produce a second reformer product stream. The secondreformer product stream can include carbon monoxide, nitrogen, hydrogen,methane, or any combination of these. The second reformer product streamand steam can be flowed to a carbon monoxide converter. The secondreformer product stream and steam can be reacted by the carbon monoxideconverter to produce a converter product stream. The converter productstream can include carbon dioxide, hydrogen, nitrogen, water, or anycombination of these. The converter product stream can be flowed to afirst condenser. The converter product stream can be cooled by the firstcondenser to separate a liquid portion of the converter product streamfrom a vapor portion of the converter product stream. The liquid portionof the converter product stream can include water. The vapor portion ofthe converter product stream can include carbon dioxide, hydrogen,nitrogen, or any combination of these. The vapor portion of theconverter product stream can be flowed to a first compressor. A pressureof the vapor portion of the converter product stream can be increased bythe first compressor. Water and the vapor portion of the converterproduct stream can be flowed to a carbon dioxide absorber. Water can becontacted with the vapor portion of the converter product stream by thecarbon dioxide absorber to facilitate transfer of carbon dioxide fromthe vapor portion of the converter product stream to the water. A waterstream can be discharged by the carbon dioxide absorber. The waterstream can include carbon dioxide, for example, transferred from thevapor portion of the converter product stream. An absorber productstream can be discharged by the carbon dioxide absorber. The absorberproduct stream can include hydrogen and nitrogen. The absorber productstream can be flowed to a second compressor. A pressure of the absorberproduct stream can be increased by the second compressor. The absorberproduct stream can be flowed to a pre-heater. A temperature of theabsorber product stream can be increased by the pre-heater. The absorberproduct stream can be flowed to an ammonia reactor. The hydrogen andnitrogen of the absorber product stream can be reacted by the ammoniareactor to produce an ammonia reactor product stream. The ammoniareactor product stream can include ammonia. The ammonia reactor productstream can be flowed to a second condenser. The ammonia reactor productstream can include hydrogen, nitrogen, or any combination of these. Theammonia reactor product stream can be cooled by the second condenser toseparate a liquid portion of the ammonia reactor product stream from avapor portion of the ammonia reactor product stream. The liquid portionof the ammonia reactor product stream can include ammonia. The vaporportion of the ammonia reactor product stream can include hydrogen,nitrogen, or any combination of these. The liquid portion of the ammoniareactor product stream can be flowed to an ammonia storage vessel. Thevapor portion of the ammonia reactor product stream can be flowed to athird compressor. A pressure of the vapor portion of the ammonia reactorproduct stream can be increased by the third compressor. The vaporportion of the ammonia reactor product stream can be flowed to thepre-heater. A temperature of the vapor portion of the ammonia reactorproduct stream can be increased by the pre-heater. The vapor portion ofthe ammonia reactor product stream can be recycled to the ammoniareactor. The switch can include a baffle. Adjusting a position of theswitch can include swinging the baffle between the first position andthe second position. The switch can include a first gate and a secondgate. Adjusting the switch to the first position can include closing thefirst gate to obstruct a flow path between the gas turbine and the waterboiler to prevent fluid from flowing from the gas turbine to the waterboiler. Adjusting the switch to the first position can include openingthe second gate to allow fluid to flow in a flow path between the gasturbine and the reformer. Adjusting the switch to the second positioncan include opening the first gate to allow fluid to flow in the flowpath between the gas turbine and the water boiler. Adjusting the switchto the second position can include closing the second gate to obstructthe flow path between the gas turbine and the reformer to prevent fluidfrom flowing from the gas turbine to the reformer.

Certain aspects of the subject matter described can be implemented as asystem. The system includes a reformer, a gas turbine, a powergenerator, a flowline, and a water boiler. The reformer is configured toreact methane with steam to produce a reformer product stream. Thereformer product stream includes carbon monoxide and hydrogen. The gasturbine is configured to rotate in response to receiving a mixture offuel and air. The power generator is coupled to the gas turbine. Thepower generator is configured to convert rotational energy from the gasturbine into electricity. The flowline fluidically connects the reformerand the gas turbine. The flowline is configured to direct exhaust fromthe gas turbine to the reformer to provide heat to the reformer. Thewater boiler is disposed within the reformer. The water boiler isconfigured to receive heat from at least one of the reformer productstream or the exhaust from the gas turbine (for example, only thereformer product stream, only the exhaust, or both the reformer productstream and the exhaust) and use the received heat to generate steam.

The details of one or more implementations of the subject matter of thisdisclosure are set forth in the accompanying drawings and thedescription. Other features, aspects, and advantages of the subjectmatter will become apparent from the description, the drawings, and theclaims.

DESCRIPTION OF DRAWINGS

FIG. 1A is a schematic diagram of an example system including a combinedcycle power generator integrated with a reformer, and a switch is in afirst position.

FIG. 1B is the system of FIG. 1A with the switch in a second position.

FIG. 1C is the system of FIG. 1A with some components omitted.

FIG. 2 is a schematic diagram of an example ammonia production systemthat includes the reformer of FIG. 1A.

FIG. 3 is a flow chart of an example method for integrating a combinedcycle power generator with a reformer.

FIG. 4 is a flow chart of an example method for integrating a combinedcycle power generator with a reformer.

DETAILED DESCRIPTION

This disclosure relates to ammonia production that integrates a powergeneration cycle with steam methane reforming in ammonia production. Thepower generation cycle includes a steam turbine, power generator, and agas turbine that can share a common shaft. Exhaust from the gas turbinecan provide heat to the steam methane reformer or a boiler thatgenerates steam. The destination for the heat can be selected based onpower demand (for example, the need for power in the form of electricityto perform operations). For example, during low power demand, theexhaust can be directed to the reformer, to improve thermal efficiencyof the ammonia production process. For example, during high powerdemand, the exhaust can be directed to the boiler, to generate steam forthe steam turbine to generate power. The subject matter described inthis disclosure can be implemented in particular implementations, so asto realize one or more of the following advantages. The systems andmethods described can be implemented to improve overall thermalefficiency of an integrated ammonia production and power generationprocess. The systems and methods described can be implemented to reducecarbon emissions of an integrated ammonia production and powergeneration process. The systems and methods described are flexible andcan be adjusted to meet variable energy demands of a processing plant.For example, during periods of high power demand, the ammonia productionand power generation processes can operate independently (that is,ammonia production process produces ammonia and power generation processgenerates power without direct cooperation with one another). In suchoperation, the overall thermal efficiency of the integrated process maydecrease. As another example, during periods of low power demand, theammonia production and power generation processes can be integrated andcooperate to produce ammonia and generate power. In such operation, theoverall thermal efficiency of the integrated process may increase.

FIG. 1A depicts a system 100 that includes a combined cycle powergenerator 102. The combined cycle power generator 102 includes a steamturbine 104, a power generator 106, a gas turbine 108, and a waterboiler 110. The steam turbine 104 is coupled to the power generator 106via a shaft 106 b. As steam flows through the steam turbine 104, thesteam turbine 104 rotates. The power generator 106 converts therotational energy of the steam turbine 104 into electricity. The gasturbine 108 is coupled to the power generator 106 via the shaft 106 b.As gas (for example, a mixture of fuel gas 109 and air 111) flowsthrough the gas turbine 108, the gas turbine 108 rotates. In someimplementations, the gas that flows to the gas turbine 108 is compressed(for example, by a compressor) to increase the pressure of the gas. Insome implementations, the gas flowing through the gas turbine 108 isignited to increase to temperature of the gas. The power generator 106converts the rotational energy of the gas turbine 108 into electricity.In some implementations, at least a portion of the rotational energy ofthe gas turbine 108 is used to compress the gas upstream of the gasturbine 108. For example, at least a portion of the shaft work producedby the gas turbine 108 is used to drive the compressor. The shaft 106 bcan be a single shaft or multiple shafts coupled together end-to-end.

The water boiler 110 can house water and generate steam from the waterin response to receiving heat. In some implementations, the system 100includes a steam loop. In such implementations, the system 100 includesa condenser 112. Steam 113 flows through the steam turbine 104 and thento the condenser 112. The condenser 112 removes heat from the steam 113to produce liquid water 115. The water 115 flows to the water boiler 110where it receives heat to generate steam. The steam generated by thewater boiler 110 can be recycled back to the steam turbine 104 tocomplete the steam loop. In some implementations, the combined cyclepower generator 102 provides heat to the water boiler 110 to generatesteam. For example, the exhaust from the gas turbine 108 can be directedto the water boiler 110 to provide the heat necessary to generate thesteam.

The combined cycle power generator 102 is integrated with a reformer202. The reformer 202 can react methane with steam to produce a streamcomprising carbon monoxide and hydrogen. The combined cycle powergenerator 102 is coupled to the reformer 202. The reformer 202 is alsoshown in FIG. 2 and is described in more detail later.

Referring back to FIG. 1A, the system 100 includes a switch 114. Theswitch 114 is adjustable between a first position and a second position.In the first position, the switch 114 is configured to direct exhaustfrom the gas turbine 108 to the reformer 202. In the second position,the switch 114 is configured to direct exhaust from the gas turbine 108to the water boiler 110. In some implementations, the switch 114 is abaffle that swings between the first and second positions, depending onthe desired destination (the reformer 202 or the water boiler 110) forthe exhaust from the gas turbine 108. In some implementations, theswitch 114 includes a first gate and a second gate. In the firstposition, the first gate is closed to obstruct a flow path between thegas turbine 108 and the water boiler 110. In the first position, thesecond gate is open to leave a flow path between the gas turbine 108 andthe reformer 202 unobstructed. Thus, in the first position, the exhaustof the gas turbine 108 is directed to the reformer 202. In the secondposition, the first gate is open to leave the flow path between the gasturbine 108 and the water boiler 110 unobstructed. In the secondposition, the second gate is closed to obstruct the flow path betweenthe gas turbine 108 and the reformer 202. Thus, in the second position,the exhaust of the gas turbine 108 is directed to the water boiler 110.The position of the switch 114 may be adjusted, for example, based onenergy demands for the plant in which the system 100 is operating. Forexample, during high energy demand, the switch 114 can be adjusted tothe second position to direct heat to the water boiler 110, which canfacilitate the generation of electricity via the steam turbine 104. Forexample, during low energy demand, the switch 114 can switch to thefirst position to direct heat to the reformer 202, which can improveenergy efficiency of the system 100. FIG. 1A shows the system 100 withthe switch 114 in the first position, while FIG. 1B shows the system 100with the switch 114 in the second position. In some cases, the switch114 can be disposed in an intermediate position between the first andsecond positions, such that a first portion of the exhaust of the gasturbine 108 is directed to the reformer 202 while a second portion ofthe exhaust of the gas turbine 108 is directed to the water boiler 110.The amounts of the first and second portions of the exhaust of the gasturbine 108 flowing to the reformer 202 and the water boiler 110,respectively, can be adjusted by the switch 114 as desired.

In some implementations, the steam turbine 104 can be disconnected fromthe combined cycle power generator 102, for example, by disconnectingthe clutch connecting the steam turbine 104 to the power generator 106.For example, during periods of low power demand, the steam turbine 104can be disconnected from the power generator 106, and the exhaust fromthe gas turbine 108 can flow to the reformer 202 and not to the waterboiler 110. In some implementations, the steam loop is omitted entirely.That is, in some implementations, the system 100 does not include thesteam turbine 104, the water boiler 110, and the condenser 112. In suchimplementations, the exhaust from the gas turbine 108 flows only to thereformer 202. FIG. 1C shows an implementation of system 100 in which thesteam loop is omitted. The implementation of system 100 shown in FIG. 1Ccan be useful for configurations with low power demand. In some cases,the implementation of system 100 shown in FIG. 1C exhibits a maximumoverall thermal efficiency in comparison to the implementations ofsystem 100 shown in FIGS. 1A and 1B.

FIG. 2 depicts an ammonia production system 200 that includes thereformer 202. In some implementations, the system 100 (shown in FIGS. 1Aand 1B) is integrated with the ammonia production system 200. Theammonia production system 200 includes the reformer 202, a secondaryreformer 204, a carbon monoxide converter 206, a first condenser 208, afirst compressor 210, a carbon dioxide absorber 212, a second compressor214, a pre-heater 216, an ammonia reactor 218, a second condenser 220, athird compressor 222, and an ammonia storage vessel 224. The reformer202 includes a reformer reactor 202 a. In some implementations, thereformer 202 includes a boiler 202 b.

A feed stream 201 that includes a mixture of methane and steam flows tothe reformer reactor 202 a. The reformer reactor 202 a includes acatalyst (for example, a nickel-based catalyst) that accelerates thereaction between methane and steam to produce a reformer product stream203 that includes hydrogen and carbon monoxide (Equation 1). In somecases, carbon dioxide is also produced and included in the reformerproduct stream 203. The reformer product stream 203 can also includeunreacted methane. As shown by Equation 1, the reaction occurring withinthe reformer reactor 202 a is endothermic. Heat is provided to thereformer reactor 202 a to maintain a desired operating temperature. Heatcan be provided to the reformer reactor 202 a by combusting fuel (forexample, methane) within the reformer reactor 202 a, providing a hot gas(for example, the exhaust from the gas turbine 108), or a combination ofboth. As discussed previously with respect to system 100 shown in FIGS.1A and 1B, integrating the combined cycle power generator 102 with thereformer 202 can, for example, improve thermal efficiency.

Referring back to FIG. 2 , in some implementations, fuel (for example,methane) is combusted within the reformer reactor 202 a to provide heat.The boiler 202 b can be positioned within the reformer 202 (for example,within a housing of the reformer 202), such that the heat produced fromcombustion of the fuel within the reformer reactor 202 a can betransferred from the hot gases flowing in the reformer 202 (and aroundthe boiler 202 b) to the boiler 202 b. In some implementations, thereformer product stream 203 flows through the boiler 202 b to provideadditional heat. The heat provided to the boiler 202 b is used togenerate steam 201 a. In some implementations, the steam 201 a generatedby the boiler 202 b supplies at least a portion of the steam in the feedstream 201.CH₄+H₂O→CO+3H₂ΔH=+206 kJ/mol  (1)

The reformer product stream 203 flows to the secondary reformer 204. Aheated stream 205 also flows to the secondary reformer 204. The heatedstream 205 includes oxygen. The heated stream 205 can include nitrogen.For example, the heated stream 205 can be heated air. At least a portionof the methane in the reformer product stream 203 reacts with oxygen inthe secondary reformer 204 to produce additional hydrogen (Equation 2).A second reformer product stream 207 including carbon monoxide,nitrogen, and hydrogen exits the secondary reformer 204.2CH₄+O₂→2CO+4H₂ΔH=−71 kJ/mol  (2)

The second reformer product stream 207 flows to the carbon monoxideconverter 206. Steam 209 also flows to the carbon monoxide converter206. A water-gas shift reaction occurs in the carbon monoxide converter206 to convert carbon monoxide to carbon dioxide and produce additionalhydrogen (Equation 3). A converter product stream 211 including carbondioxide, hydrogen, and nitrogen exits the carbon monoxide converter 206.The converter product stream 211 can also include unreacted water.CO+H₂O→CO₂+H₂ΔH=−41 kJ/mol  (3)

The converter product stream 211 flows to the first condenser 208. Thefirst condenser 208 cools the converter product stream 211 and causesthe steam in the converter product stream 211 to condense. The liquidportion 211 a of the converter product stream 211 exits the firstcondenser 208. The vapor portion 211 b of the converter product stream211 exits the first condenser 208 and flows to the first compressor 210.The first compressor 210 increases the pressure of the vapor portion 211b.

The vapor portion 211 b includes carbon dioxide, hydrogen, and nitrogenand flows to the carbon dioxide absorber 212. A water stream 213 a issprayed within the carbon dioxide absorber 212 to scrub carbon dioxidefrom the vapor portion 211 b. In some implementations, the carbondioxide absorber 212 includes a packed bed to improve mass transfer ofcarbon dioxide from the vapor portion 211 b to the water stream 213 a.The packed bed can include random packing, structured packing, or both.A water stream 213 b that includes carbon dioxide (for example,dissolved) from the vapor portion 211 b exits the carbon dioxideabsorber 212. An absorber product stream 215 including hydrogen andnitrogen exits the carbon dioxide absorber 212.

The absorber product stream 215 flows to the second compressor 214. Thesecond compressor 214 increases the pressure of the absorber productstream 215, such that the absorber product stream 215 has a desiredoperating pressure once it reaches the ammonia reactor 218. The absorberproduct stream 215 flows from the second compressor 214 to thepre-heater 216. The pre-heater 216 increases the temperature of theabsorber product stream 215, such that the absorber product stream 215has a desired operating temperature once it reaches the ammonia reactor218. The absorber product stream 215 flows from the pre-heater 216 tothe ammonia reactor 218. The ammonia reactor 218 includes a catalyst(for example, an iron-based catalyst) that accelerates the reactionbetween hydrogen and nitrogen to produce an ammonia reactor productstream 217 that includes ammonia (Equation 4). The ammonia reactorproduct stream 217 can also include unreacted gas (hydrogen, nitrogen,or both).3H₂+N₂→2NH₃ΔH=−46 kJ/mol  (4)

The ammonia reactor product stream 217 flows to the second condenser220. The second condenser 220 cools the ammonia reactor product stream217 and causes the ammonia in the ammonia reactor product stream 217 tocondense. The liquid portion 217 a of the ammonia reactor product stream217 exits the second condenser 220 and flows to the ammonia storagevessel 224. The vapor portion 217 b of the ammonia reactor productstream 217 includes unreacted hydrogen and/or nitrogen and exits thesecond condenser 220 and flows to the third compressor 222. The thirdcompressor 222 increases the pressure of the vapor portion 217 b, suchthat the vapor portion 217 b has the desired operating pressure once itreaches the ammonia reactor 218. The vapor portion 217 b can be recycledto the ammonia reactor 218. For example, the vapor portion 217 b mixeswith the absorber product stream 215 downstream of the second compressor214 and upstream of the pre-heater 216. The pre-heater 216 can increasethe temperature of the vapor portion 217 b, such that the vapor portion217 b has the desired operating temperature once it reaches the ammoniareactor 218.

FIG. 3 is a flow chart of a method 300 for integrating a combined cyclepower generator (102) with a reformer (202). At block 302, methane andsteam is flowed to the reformer 202. At block 304, the methane and steamare reacted by the reformer 202 to produce a reformer product stream(203). At block 306 a, steam is flowed to a steam turbine (104), therebycausing the steam turbine 104 to rotate. At block 306 b, electricity isgenerated by a power generator (106) coupled to the steam turbine 104 inresponse to rotation of the steam turbine 104. At block 308 a, fuel andair are flowed to a gas turbine (108), thereby causing the gas turbine108 to rotate. At block 308 b, electricity is generated by the powergenerator 106 coupled to the gas turbine 108 in response to rotation ofthe gas turbine 108. At block 310, exhaust from the gas turbine 108 isdirected, by a switch (114) in a first position, to the reformer 202 toprovide heat to the reformer 202. The switch 114 can be adjusted fromthe first position to a second position, thereby directing, by theswitch 114 in the second position, exhaust from the gas turbine 108 to awater boiler (110) to provide heat to the water boiler 110. Steam can begenerated by the water boiler 110 in response to receiving heat via theexhaust from the gas turbine 108.

FIG. 4 is a flow chart of a method 400 for integrating a combined cyclepower generator (102) with a reformer (202). In a first scenario, thepower demand is low. Fuel (for example, methane or a mixture ofhydrocarbons) flows to a gas turbine (108). The fuel is combusted andflows through the gas turbine 108 to generate power. The exhaust fromthe gas turbine 108 flows to the reformer 202 to provide heat. Methaneis flowed to the reformer 202, for example, mixed with steam as feed forthe methane reforming process (Equation 1). As mentioned previously, themethane reforming process is endothermic, so the reformer 202 needs heatinput to maintain a desired operating temperature range. The exhaustfrom the gas turbine 108 can be a source of heat to the reformer 202. Inthe first scenario, the steam turbine (104) can be disconnected from thecombined cycle power generator 102.

In a second scenario, the power demand is high. Fuel (for example,methane or a mixture of hydrocarbons) flows to the gas turbine 108. Thefuel is combusted and flows through the gas turbine 108 to generatepower. The exhaust from the gas turbine 108 flows to a boiler (110) togenerate steam (113). The steam 113 flows to a steam turbine (104) togenerate additional power. Fuel (for example, methane or a mixture ofhydrocarbons) flows to a furnace of the reformer 202 and is combusted toproduce heat. Methane is flowed to the reformer 202, for example, mixedwith steam as feed for the methane reforming process (Equation 1). Asmentioned previously, the methane reforming process is endothermic, sothe reformer 202 needs heat input to maintain a desired operatingtemperature range. The combustion of the fuel flowing to the furnace ofthe reformer 202 can be a source of heat to the reformer 202.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of what may beclaimed, but rather as descriptions of features that may be specific toparticular implementations. Certain features that are described in thisspecification in the context of separate implementations can also beimplemented, in combination, in a single implementation. Conversely,various features that are described in the context of a singleimplementation can also be implemented in multiple implementations,separately, or in any sub-combination. Moreover, although previouslydescribed features may be described as acting in certain combinationsand even initially claimed as such, one or more features from a claimedcombination can, in some cases, be excised from the combination, and theclaimed combination may be directed to a sub-combination or variation ofa sub-combination.

As used in this disclosure, the terms “a,” “an,” or “the” are used toinclude one or more than one unless the context clearly dictatesotherwise. The term “or” is used to refer to a nonexclusive “or” unlessotherwise indicated. The statement “at least one of A and B” has thesame meaning as “A, B, or A and B.” In addition, it is to be understoodthat the phraseology or terminology employed in this disclosure, and nototherwise defined, is for the purpose of description only and not oflimitation. Any use of section headings is intended to aid reading ofthe document and is not to be interpreted as limiting; information thatis relevant to a section heading may occur within or outside of thatparticular section.

As used in this disclosure, the term “about” or “approximately” canallow for a degree of variability in a value or range, for example,within 10%, within 5%, or within 1% of a stated value or of a statedlimit of a range.

As used in this disclosure, the term “substantially” refers to amajority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%,95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999%or more.

Values expressed in a range format should be interpreted in a flexiblemanner to include not only the numerical values explicitly recited asthe limits of the range, but also to include all the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range is explicitly recited. For example, arange of “0.1% to about 5%” or “0.1% to 5%” should be interpreted toinclude about 0.1% to about 5%, as well as the individual values (forexample, 1%, 2%, 3%, and 4%) and the sub-ranges (for example, 0.1% to0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. Thestatement “X to Y” has the same meaning as “about X to about Y,” unlessindicated otherwise. Likewise, the statement “X, Y, or Z” has the samemeaning as “about X, about Y, or about Z,” unless indicated otherwise.

Particular implementations of the subject matter have been described.Other implementations, alterations, and permutations of the describedimplementations are within the scope of the following claims as will beapparent to those skilled in the art. While operations are depicted inthe drawings or claims in a particular order, this should not beunderstood as requiring that such operations be performed in theparticular order shown or in sequential order, or that all illustratedoperations be performed (some operations may be considered optional), toachieve desirable results. In certain circumstances, multitasking orparallel processing (or a combination of multitasking and parallelprocessing) may be advantageous and performed as deemed appropriate.

Moreover, the separation or integration of various system modules andcomponents in the previously described implementations should not beunderstood as requiring such separation or integration in allimplementations, and it should be understood that the describedcomponents and systems can generally be integrated together or packagedinto multiple products.

Accordingly, the previously described example implementations do notdefine or constrain the present disclosure. Other changes,substitutions, and alterations are also possible without departing fromthe spirit and scope of the present disclosure.

What is claimed is:
 1. A system comprising: a reformer configured toreact methane with steam to produce a reformer product stream comprisingcarbon monoxide and hydrogen; a combined cycle power generatorfluidically coupled to the reformer, the combined cycle power generatorcomprising: a steam turbine connected to a first end of a common shaftand configured to rotate the common shaft in response to receivingsteam; a gas turbine connected to a second end of the common shaft andconfigured to rotate the common shaft in response to receiving a mixtureof fuel and air; a power generator coupled to the common shaft, thepower generator configured to convert rotational energy from the commonshaft into electricity; and a water boiler fluidically coupled to thesteam turbine and configured generate steam in response to receivingheat; and a switch that can adjust between a first position and a secondposition, wherein in the first position, the switch is configured todirect exhaust from the gas turbine to the reformer, and in the secondposition, the switch is configured to direct exhaust from the gasturbine to the water boiler; wherein the reformer is a part of anammonia production system; the reformer comprises a reformer reactor anda second water boiler; the reformer reactor is configured to dischargethe reformer product stream; the reformer product stream comprisesmethane; and the second water boiler is configured to generate steam inresponse to receiving the reformer product stream.
 2. The system ofclaim 1, wherein the switch comprises a baffle configured to swingbetween the first position and the second position.
 3. The system ofclaim 1, wherein the switch comprises a first gate and a second gate,wherein: in the first position, the first gate is closed and configuredto obstruct a flow path between the gas turbine and the water boiler toprevent fluid from flowing from the gas turbine to the water boiler,while the second gate is open and configured to allow fluid to flow in aflow path between the gas turbine and the reformer; and in the secondposition, the first gate is open and configured to allow fluid to flowin the flow path between the gas turbine and the water boiler, while thesecond gate is closed and configured to obstruct the flow path betweenthe gas turbine and the reformer to prevent fluid from flowing from thegas turbine to the reformer.